If alerts

We now have two types of alert. I've made them a component and will go around and update other alerts in apps to use the new ones. I know there were some issues with alerts in thorntree using hyperlinks and not working with a component so will look at that (still useful everywhere else).

![image](https://cloud.githubusercontent.com/assets/814861/3808184/508fb23e-1c73-11e4-8516-ce037ce3d3f3.png)